Surkavir, Tyrant of the North

As long as Surkavir, Tyrant of the North isn't attacking, other Goblin creatures you control gain
+1/+1.
Whenever Surkavir, Tyrant of the North attacks,
he gains +X/+0 until the end of the turn, where X equals the number of other attacking Goblins you control.
{1}{r}: Other Goblins you control gain +1/+0 until
the end of the turn.
Goblins follow Surkavir, but scavengers follow the
Northern Legion, for where they go, carnage is sure to follow.